1. Field of the Disclosure
This disclosure generally relates to an optical sensing element, more particularly, to a distance measurement device based on phase difference and a distance measurement method thereof.
2. Description of the Related Art
In general, a distance measurement system employs a light source and calculates an object distance according to energy of light beam of the light source reflected back by the object. Traditionally, it is able to calculate the distance using the triangulation method or time-of-flight (TOF) technique. However, the above methods require a higher cost and larger system size.
In addition, the development of gesture recognition generally removes the background image at first by using a 3D image in order to separate the foreground image. In this technique, two image sensors are used such that the size and cost of a gesture recognition module can not be effectively reduced.
As mentioned above, the present disclosure obtains a 3D image by using the phase detection, and an additional illumination light (as used in the TOF technique mentioned above) is not required. Meanwhile, in the proposed technique of the present disclosure, the distance measurement and the gesture recognition are implemented by only employing a single image sensor.